Ab initio prediction of the first and second pressure derivatives of isothermal bulk modulus for the high-pressure rocksalt phase of ZnO

► The bulk moduli KT and Ks of rocksalt ZnO have been investigated using ab initio method. ► The quasi-harmonic Debye model is applied to take into account the thermal effect. ► Particular attention is paid to the predictions of the KT, KT′, and KT″ of rocksalt ZnO.